Furnace peep sight



Patented Sept. 11, 1934 UNITED STATES PATENT OFFICE FURNACE rani sIGHTWilliam H. iacobi, Keokuk, Iowa, assignor to Springfield Boiler Co.,Springfield, Ill., a cer--` poration of Illinois The general object ofthe present inventon is the improvement of means provided to permitvisual inspection of the interier of a furnace chamber, such as thecombustion cha'mber of a boiler urnace, in which high temperatures aremaintained. More specific objects of the invention are to provide simpleand effective means for opening and closing a peep hole in a urnacewall, and for protecting an operator inspecting the interior of thefurnace through' said peep hole, against injury from furna'ce heat orglare and for preventing an objectionable i'nflux 'oi air or outflow offurnace gases through the peep hole while the interior of the furnace isbeing inspected.

'A preferred embodinent of the present invention comprises a peep holedoor adjustable to place either a transparent portion or a less frangible opaque portion of the door in register with the peep hole proper,and preferably adjustable also to move the door entirely out of registerwith 'the peep hole so that a slice'bar, steam lance or likeinstrumentality may be inserted in the peep hole. The door and itssupporting means are characterized by their mechanical Simplicity andeffectiveness, and 'by the easy and effective man ner in'which they maybe mounted on a fire door, masonry or other portion of a furnace wall.The invention is further characterized by the provisions made forprotecting the glass forming the transparent portion of the door againstnjury from the high temperature to which it is sub- I jected when inregister with the peep hole.

The various features of novelty which characterize my invention arepointed out withparticularity in the claims annexed to and forining apart of this specification. For a better understanding of the invention,however, and the advantages possessed by it, reference should be had tothe accompanying drawing and desoriptive matter in which I haveillustrated and described a preferred embodiment of the invention.

Of the drawing:-`

Fig. 1 is a sectional elevation of a portion of a furnace wall providedWith a peep ho le;

Fig. 2 is an elevation of the peep hole door and doorway; i

Figs. 3 and 4 are views taken similarly to Fig. 2 with the movable doorshownin dierent positions; and

Fig. 5 is a partial section on the line 5--5 of Fig. 2. i i

In the drawing, A represents the wall of a furl nace chamber, such asthe combustion chamber of the boiler furnace, in which high temperaturesof the` opening A'.

are maintained, and A' represents a peep hole opening formed in the wallproper. When the peep hole is formed in a masonry portion of the furnacewall, the peep hole is advantageously conical in form with its outer endsmaller than its inner end. In'such case also, the peep hole isadvantageously provided with a lining A formed of suitably shaped tilesor refractory cement.

- Attached to the furnace wall at its outer side, as by means of bolts-B' imbedded in the lining A is a metallic peep hole door frame B. The'latter is advantageously formed, as shown, with a plate-like bodyportion B having a. hollow boss or tubular extension 13 at its outer:side, the axis of the passage in which is in line with the axis Theouter end of the hollow boss B forms a seat 13 for a door member C shownas hinged by a pivot pin'c' to a lug B formed on the tubular portion 13of the member 315 B. The doormember C comprises a portion C of suitablethickness to insure durability, which normally engages the seat 13 andcloses the peep hole `as shown in Figs. 1 and 2. The door mem- .ber C isformed with a Window opening C which is brought into register with thepeep hole when the member C is in the position shown in Fig. 3. Theparts Band C may advantageously be formed of cast iron or steel, or oi amore refractory metal alloy in some cases. r i

The door member C supports a transparent body or window pane D whichextends across the openingC The window pane D is preferably in the formof a disc made of highly refractory glass, and the gla'ss isadvantageously colored to cut down the transmission of heat and lightrays while: leaving the glass sufiiciently transparent. As shown, theglass D is held between annular clamping members E and E' Secured to thebody portion of the door C, as by screws E `'I'o reduce the risk ofoverheating the glass D, I advantageously nterpose a'wire screen Fbetween the glass D and the interior of the furnace. This screen F maybe formed of Monel metal or other metal wellsadapted to withstand hightemperatures. As shown, the' screen F is clamped between the body ofthe, door C -at the margin of the opening C and the clamping ring E', sothat the screen is in good heat conducting relation with the door andclamping rings. quence it Will be maintained at a relatively lowtemperature, and partly by intercepting heat rays and partly byabsorbing heat by radiation from the inner face of the glass D, thescreen F is thus effective to prevent the glass D from attaining Inconsean objectionably high temperature during the period:: in which theglass is exposed to the heat of the urnace through the peep hole. As afurther protection against injury of the glass when the latter is heatedand cooled I advantageously form a small aperture in the glass at orabout its center. Thisapertu'e serves, as I have found, tosubstantially'reduce the risk of glass fracture as a result of itsthermal eXpansion and contraction.

In the preferred Construction illustrated the adjustment of the door Cis facilitated by providing it with a handle G mounted on a:pivot pin Gearried by cars 0 formed for the purpose on the door. The handle G isadvantageously provided with a tongue Gr adapted to enter the spacebetween a pair of lugs B formed on the boss B when the door is in itsnormalor closed position of the apparatus as shown in Figs. 1 and 2. Asshown, the tongue G is formed with oppositely projecting portions (3constituting lock bar parts which in'the position of the parts shown inFigs; l and 2, are behind the lugs B so that the door is then snuglyheld'in its closed position. g

Advantageousiy and as shown, the door C is provided with a stop C whichengages the boss `B when the parts are turned into the position .shownin Fig. 3. 'It is contemplated that the door will be manually held inthe position shown in `E'ig. 3 by the operator inspecting the furnace,during 'the inspection periods, and the stop 0 assists the operator inholding the door in proper position for inspection ipurposes. `Asappears sfromrFig. 4, the stop C may also seri/ethe further purpose ofholding the cloormemberC in the position in which no 'portion of thedoor memberC extendsacross the `peep hole opening. When the door is inthe ;position shown in Fig. 4, 'the action of 'gravity tends to maintainit 'in that position.

Except when in the "position shown in Fig.- 4, gravity tends to hold thedoor 'in its normally :closedposition shown in Figs. 1 and.2.

In the position of the door shown in Fig. 4,'a

slice bar, steam lance or'analogous :instrumen- 'FandcglassD are:brought'into position above "the boss'B fto permit :theremoval offurnace dust eaccumulating on the door parts and impairing`thetransparency of the glass D. While the present invention may be usedin connection with peepholes 'of varioussizes, 'ithas been foundconvenient and desirable 'inlthe use of the present inventionto make theminimum diameter of the :peep hole iapproximately five inches, as a hole`nisur-;h size :is convenient and suitable not only foriinspectionpurposes, but also for the insertion and manipulation of a slice bar,steam lance or liker instrumentality.

'As those skilled in theart will readily understand, the constructionillustrated is simple, dur- 'able and efiective, and' is relativelyinexpensive tomanufacture .and install. It can bereadily attached toaurnace fire or :inspection door as well as 'to brick work, and may bemounted on the brick work of `the furnace without requiring 'obi'jectionabl'e modfication'of *suchbrick work. The

provision of a suitable inspection opening or `-'openings facilitated bythe use of the present invention, contributes to efiiciency in furnaceop- :in the art that changes may be made in the form of the apparatusdisclosed without departing from the spiritof my invention as set forthin the appended claims and that in some cases certain features of myinvention may be used to advantage without a corresponding use of otherfeatures.

Having now described my invention, what I ;claim as new and desire tosecure by Letters Patent is:-

l. A furnace peep hole door Construction com- :prising a door framememberadapted to be attached to a substantially vertical wall of 'thefur-hace and formed with an outwardly projecting bosshaving apeep holepassage therethrough, a

door member pivotally connected to said frame member to ireely turn withrespect thereto in 'a Vertical plane about an axs at one side of saidpassage into cne `or another of three positions and comprising atransparent portion in register with said passage in one .of saidpositions and an opaque portion in register with said passage in anotherof said positions, :said door member being out of 'line with saidpassage in the third position, a projection carried by said door memberand engaging said boss .when the door member is in said third position,said members being so relatively arranged that when the door member isinsaidthirdpositiongravity tends .to maintain the door member in said,position and when in said first position gravity `tends to move thedoor member into said second position.

2. A furnace peep hole door Construction comprising adoorrame member.adapted to be attached to the wall of `the lfurnace .and formed withan'outwardly p'ojecting boss having a .peep hole passage therethrough, adoormem'ber pivotally connected `to said framelmember to turn withrespect thereto in -a vertical plane about an axis at one side of saidpassage into one or another of three positions and .comprising a'transparent portion in register with said passage in one of saidpositions and an opaque portion in register with said passage inanotherof said positions, said door .member being out of line with said passagein the third position, said members having cooperatingpositioning.partspositively' indicating when said door member is in anyone of said three positions.

3. The combination with a substan'tially .vertical wall of `a furnacechamber having a peep hole extending through said wall, of a structureat the outer end of said peep hole comprising a 'for'the passage ofcooling air to the furnace side thereof. i

4. The combination with a substantially Vertical wall of a furnacechamber having a peep hole extending through said wall, of a structureat the outer end of said peep hole comprising a frame formed with anopening substantially registering with said peep hole, and a doorarranged to be swung in a vertical plane parallel to the plane of said.opening to a plurality of operating positions, a transparent membermounted in said door and arranged to register with said opening in oneposition of said. door, a small central aperture in said member for thepassage of cooling air to the fu'naoe side thereof, and. a Wire screenmounted in said door at the furnaoe side of said member and in goodheatconducting re lation with said door.

5. A furnace peep hole door structure including a transparent member ofcolored glass having one side exposed to the interier of a furnace andits other side to atmosphere and mounted in a movable part of said doorstructure, said member being formed with a small central aperture forthe passage of cooling air to the furnace side of said member.

6. A furnace peep hole door construction comprising a door frame memberadapted to be attached to a substantially vertical wall of the furnaceand formed. with an outwardly projecting boss having a peep hole passagetherethrough, a door member pivotally connected to said frame member toturn with respect thereto in a vertical plane about an axis at one sideof said. passage into one or another of three positions and comprising atransparent portion registering with said passage in one of saidpositions and an opaque portion register-ing with said. passage inanother of said positions, said door member being out of register withsaid. passage in the third position, a projection carried by said doormember and engaging said boss when the door member is in said first andthird mentioned positions, said members being so relatively arrangedthat when the door member is in said third position gravity tends tomaintain the door member in said position and when in said firstposition gravity tends to move the door member into said secondmentioned position, and means for looking said door member in saidsecond position.

WILLIAM H. JACOBI.

